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6.
FOREWORD
The book on “PROCESS PLANNING AND COST ESTIMATION” by Dr. R. Kesavan
et al. is a good attempt towards making a textbook for the students of Engineering and Technology.
The book is written in five chapters in simple language, which will help the students immensely.
The authors have taken pains in explaining in detail the concepts and the nuances of Cost Estimation
and the steps involved in Process Planning. A number of illustrations make the book eminently
readable.
I congratulate the authors for attempting to write a book on such an important subject.
S. NATARAJAN
Professor and Head
Department of Mechanical Engineering
College of Engineering, Guindy
Anna University, Chennai - 600 025.

8.
PREFACE TO THE SECOND EDITION
This edition of “Process Planning and Cost Estimation” is based on the syllabus of B.E., B.Tech.—
Mechanical, Production, Metallurgy and Industrial Engineering courses. It is also a valuable asset
for entrepreneurs, training managers of various mechanical workshops and diploma students.
Valuable suggestions and constructive criticism from number of colleagues at various institutions
and the feedback from the students as well as our friends motivate us to write this second edition.
The second edition of this book has been presented in a simple and systematic way with
numerous diagrams and number of solved problems and review questions. This edition provides all
necessary information about process planning and cost estimation for various products, work study,
ergonomics and production cost estimation.
We are grateful to our management for their continuous support in bringing out this book
successfully. Suggestions for improvement are most welcomed and would be incorporated in the
next edition to make this book more useful.
Dr. R. KESAVAN
C. ELANCHEZHIAN
B. VIJAYA RAMNATH

10.
PREFACE TO THE FIRST EDITION
This edition of “Process Planning and Cost Estimation” is based on the latest syllabus of B.E.,
B.Tech.— Mechanical and Production Engineering. It is a valuable asset for entrepreneurs, training
managers of various mechanical workshops, and diploma students.
This book is an attempt to provide all necessary information about process planning and cost
estimation. The subject matter has been presented in a simple and systematic way with numerous
diagrams and illustrations so as to make thorough understanding of the topics.
We have put our best efforts to provide solved problems and excellent exercise problems at
the end of each chapter. Various complex topics have been discussed pointwise and supported by
practical example problems wherever possible. To apprise the student about expected type of
questions which can be asked in the examinations, important review questions have been provided
at the end of each chapter.
We thank the publishers who have come forward to publish this book.
Suggestions for improvement of this book are welcomed and would be incorporated in the next
edition to make it more useful.
Dr. R. KESAVAN
C. ELANCHEZHIAN
B. VIJAYA RAMNATH

18.
Unit–1
WORK STUDY
1.0 WORK STUDY
The main problem in our country is poor standard of living of most of our population. More than
70% of our people live in very poor living conditions. They are not in a position to satisfy their
basic needs like food, cloth and shelter.
If we want to raise the standard of living of our people we must produce goods at a lesser
cost. This can be done only by increasing the efficiency of production. Efficiency in production is
known as productivity. There are many techniques used for increasing productivity. Work study is
one of the technique for improving productivity and hence raise the standard of living.
Definition: Work study is a generic term for the techniques of method study and work measurement.
These techniques are used in the examination of human work in all its contexts. They lead
systematically to the investigation of all the factors which affect the efficiency and economy at the
work place in order to affect improvement.
Work study was previously known as time and motion study. This was developed by F.W.Taylor
and Frank B.Gilberth.
1.1 IMPROVING PLANT LAYOUT
Work study consists of method study and work measurement. Work study is considered as an
important tool in increasing productivity because of the following reasons.
1. By method study,
Working condition is improved.
Work content is reduced.
Worker’s efficiency is increased.
Plant layout is improved.
2. By work measurement,
Ineffective time is reduced.
Production time is standardized.
It helps in planning and controlling.

19.
2
Process Planning and Cost Estimation
Work study can be applied to any field of activity. The increase in productivity can be achieved
immediately. It needs very less investment. Work study finds out the defects in the organization.
Work study is always the first technique applied for increasing productivity.
Hence, work study is considered as a valuable tool in increasing productivity.
1.2 IMPORTANCE OF WORKING CONDITIONS
Working conditions mean the physical conditions and facilities available in the working place. They
are
1. Lighting and ventilation.
2. Temperature and humidity.
3. Safety and healthy.
4. Layout and house keeping.
5. Noise and vibration.
6. Ergonomics.
Bad working conditions will affect the performance of the workers. The worker will not be
able to work efficiently. So, production is affected. Workers will not be regular in their duty. Because
of the bad working conditions, the workers may even resign their job. If work study is done in bad
working condition, it will give inaccurate results. Only in good working conditions, the workers will
give their normal performance. The different working conditions are explained here.
1. Lighting and Ventilation
Lighting: For doing any work, proper lighting is essential. Proper lighting will lead to the increased
production and hence increased productivity. Improper lighting will cause headache, visual fatigue
and avoidable accidents.
Level of lighting required will depend upon the type of works viz., casual work, rough work,
fine work, inspection work etc. As a general rule, lighting should be uniformly spread. Natural light
should be used wherever possible. Artificial light should add to natural light to give uniform light.
Glare should be avoided. Fluorescent light with anti-glare fitting is ideal for industrial applications.
Ventilation: Ventilation means free and fresh supply of air. Insufficient air circulation will affect
the health of workers. It leads to fatigue of workers. It reduces productivity. Therefore, good
ventilation must be provided. Recommended minimum air flow is 50 cubic metres per hour. Fumes,
smokes and dusts should be driven out using exhaust fans. Main function of ventilation are
Dispersal of atmospheric contaminations.
Dispersal of heat generated by men and machines.
Maintaining correct level or oxygen, carbon dioxide and carbon monoxide.
2. Temperature and Humidity
High temperature and humidity in the shop floor will cause fatigue to workers. In deep mines, textile
mills and sugar mills, ventilation will be poor and relative humidity will be high. So working condition
will be very poor. Humidity must be controlled by proper means. More rest during work must be
provided.
Similarly, workers working at low temperature must be provided with suitable clothing and
footwear. They must be given periodic exposure to normal temperature. They must be provided

20.
Work Study
3
with not drinks at regular intervals. The air temperature normally recommended is 20° to 22°C for
light physical work and 14° to 16°C heavy work in standing position.
3. Safety and Health
Safety of workers in the work place is very important. Management must provide safe environment
to the workers and prevent occurrence of accidents. Only when the workers feel that they are in
an accident free environment, they can give maximum output.
Safe workplace layout should be provided with safe material handling methods. Personal
protective devices for protecting head, face, eyes, lungs and other body parts like hand, foot and
legs should be provided.
Clean workplace with healthy environment must be provided to protect workers against infection
and occupational diseases.
4. Layout and Housekeeping
Good workplace layout and housekeeping play important roles in providing better working condition.
Workplace should have
1. Sufficient window area—at least 20% of floor area.
2. Ceiling height should be at least 3 metres.
3. Every workers should be provided with at least 10 cubic metres of air and a free floor
area of 2 square metres.
4. Traffic aisles should be wide enough to allow free movement of material handling equipment
and workers.
5. Floor should be non-slip, non-dust forming and easy to clean.
A good house keeping should be ensured in the plant. There should be a place reserved for
every material and every material should be stored in its place. Tools and other production aids
must be stored systematically in their own locations. In process materials should be kept in such a
way that they do not obstruct the free movement of men and material.
5. Noise and Vibration
Noise: Noise is defined as unwanted sound to which an individual is exposed. In industries, almost
all machines generate noise and this must be reduced to the lowest level. The effects of noise are
1. Disturbs concentration and causes annoyance.
2. Interferes with speech communication.
3. Causes hearing losses to workers.
4. Increases fatigue and blood pressure.
Exposure to continuous noise above 90 dB is dangerous for hearing. Noise level can be controlled
in the following ways:
1. Replacing noisy machine and equipment.
2. Dynamically balancing rotating parts.
3. Using rubber and plastic components wherever possible.
4. Separating the noise sources with brick walls.
5. Using ear plugs and protecting the ears.
Vibration: Vibration is created by
1. Rotating components.

21.
4
Process Planning and Cost Estimation
2. Machines during hand grinding.
3. When using pneumatic chipping and riveting hammers.
When one’s body is in contact with vibration source continuously, it may lead to
1. Loss of sense of touch and temperature in fingers.
2. Muscular weakness.
3. Loss of mental alertness.
4. Pain and stiffness in joints.
Vibrations can be controlled by the following means.
1. Control at source by balancing all revolving parts.
2. Reducing speed of rotating parts.
3. Maintaining machineries and tools regularly.
4. Protecting the workers by minimizing the exposure and providing rest breaks.
6. Ergonomics
Ergonomics can be defined as human engineering which studies the relationship between man and
his working environment. Ergonomic process attempts to fit the job to the worker. It aims at
1. Designing the workplace to fit the requirement of the worker.
2. Designing the equipment, machines and controls to minimize physical and mental strain to
the workers.
3. Providing a favourable environment for working.
The workplace should be designed for the use of the specific worker whose dimensions are
known. It may be designed to suit a group of persons. It can be adjusted to suit the individuals.
Workplace layout, design of seat and arrangement of different equipment should not cause
discomfort to workers. Proper foot rest, arm rest and leg room must be provided. Design and location
of various manual controls, knobs, wheels and levers should not cause excessive strain to workers.
1.3 METHOD STUDY
Method study is the technique of systematic recording and critical examination of existing and
proposed ways of doing work and developing an easier and economical method.
1.3.1 Objectives of Method Study
1.
2.
3.
4.
5.
6.
7.
8.
9.
Improvement of manufacturing processes and procedures.
Improvement of working conditions.
Improvement of plant layout and work place layout.
Reducing the human effort and fatigue.
Reducing material handling
Improvement of plant and equipment design.
Improvement in the utility of material, machines and manpower.
Standardisation of method.
Improvement in safety standard.
1.4 BASIC PROCEDURE FOR METHOD STUDY
The basic procedure for conducting method study is as follows:
1. Select the work to be studied.

22.
Work Study
2.
3.
4.
5.
6.
7.
5
Record all facts about the method by direct observation.
Examine the above facts critically.
Develop the most efficient and economic method.
Define the new method.
Install the new method
Maintain the new method by regular checking.
1. Select
While selecting a job for doing method study, the following factors are considered:
(a) Economical factors.
(b) Human factors.
(c) Technical factors.
(a) Economical Factors
The money saved as a result of method study should be sufficiently more. Then only the study will
be worthwhile. Based on the economical factors, generally the following jobs are selected.
(a) Operations having bottlenecks (which holds up other production activities).
(b) Operations done repetitively.
(c) Operations having a great amount of manual work.
(d) Operations where materials are moved for a long distance.
(b) Human Factors
The method study will be successful only with the co-operation of all people concerned viz., workers,
supervisor, trade unions etc.
Workers may resist method study due to
1. The fear of unemployment.
2. The fear of reduction in wages.
3. The fear of increased work load.
The supervisors may resist because of the feeling that their prestige may be lost.
So, the workers and supervisors must be educated about the benefits of method study. Even
then if they do not accept method study, the study should be postponed.
(c) Technical Factors
To improve the method of work all the technical details about the job should be available. Every
machine tool will have its own capacity. Beyond this, it cannot be improved. For example, a work
study man feels that speed of the machine tool may be increased and HSS tool may be used. But
the capacity of the machine may not permit increased speed. In this case, the suggestion of the
work study man cannot be implemented. These types of technical factors should be considered.
2. Record
All the details about the existing method are recorded. This is done by directly observing the work.
Symbols are used to represent the activities like operation, inspection, transport, storage and delay.
Different charts and diagrams are used in recording. They are:

23.
6
Process Planning and Cost Estimation
Sl. No.
Type of chart
Purpose
1.
Operation process chart
All the operations and inspections are recorded.
2.
Flow process chart
(a) Man type
(b) Material type
(c) Equipment type
All the activities of man are recorded
All the activities of the material are recorded
All the activities of equipment or machine are recorded.
3.
Two-handed process chart or
Right hand-Left hand chart
Motions of both lands of worker are
recorded independently.
4.
Multiple activity chart
Activities of a group of workers doing a single job or the
activities of a single worker operating a number of
machines are recorded.
5.
Flow diagram
This is drawn to suitable scale. Path of flow of material
in the shop is recorded.
6.
String diagram
The movements of workers are recorded using a string
in a diagram drawn to scale.
Note: The different charts and diagrams are explained in detail at the end of this chapter.
3. Examine
Critical examination is done by questioning technique. This step comes after the method is recorded
by suitable charts and diagrams.
The individual activity is examined by putting a number of questions.
The following factors are questioned
1. Purpose
– To eliminate the activity, if possible.
2. Place
– To combine or re-arrange the activities.
3. Sequence –
-do4. Person
–
-do5. Means
– To simplify the activity.
The following sequence of questions is used:
1. Purpose
– What is actually done?
Why is it done?
What else could be done?
What should be done?
2. Place
– Where is it being done?
Why is it done there?
Where else could it be done?
Where should it be done?
3. Sequence – When is it done?
Why is it done then?
When could it be done?
When should it be done?
4. Person
– Who is doing it?

24.
Work Study
7
Why does that person do it?
Who else could do it?
Who should do it?
5. Means
– How is it done?
Why is it done that way?
How else could it be done?
How should it be done?
By doing this questioning unwanted activities can be eliminated. A number of activities can be
combined or re-arranged. The method can be simplified. All these will reduce production time.
4. Develop
The answer to the questions given below will result in the development of a better method.
1. Purpose
– What should be done?
2. Place
– Where should it be done?
3. Sequence – When should it be done?
4. Person
– Who should do it?
5. Means
– How should it be done?
Development of a better method is explained in the following example.
In sending letters to the customers it was found that the address of the customer was typed
twice. The address was typed in the letter and also over the cover. By the questioning technique,
typing on the cover was eliminated. A window cover was devised and used.
5. Define
Once a complete study of a job has been made and a new method is developed, it is necessary to
obtain the approval of the management before installing it. The work study man should prepare a
report giving details of the existing and proposed methods. He should give his reasons for the changes
suggested. The report should show
(a) Brief description of the old method.
(b) Brief description of the new method.
(c) Reasons for change.
(d) Advantages and limitations of the new method.
(e) Savings expected in material, labour and overheads.
(f) Tools and equipment required for the new method.
(g) The cost of installing the new method including.
1. Cost of new tools and equipment.
2. Cost of re-layout of the shop.
3. Cost of training the workers in the new method.
4. Cost of improving the working conditions.
Written standard practice: Before installing the new method, an operator’s instructions sheet
called written standard practice is prepared. It serves the following purposes:
1. It records the improved method for future reference in as much detail as may be necessary.
2. It is used to explain the new method to the management foreman and operators.
3. It gives the details of changes required in the layout of machine and work places.
4. It is used as an aid to training or retraining operators.
5. It forms the basis for time studies.

25.
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Process Planning and Cost Estimation
The written standard practice will contain the following information:
(a) Tools and equipment to be used in the new method.
(b) General operating conditions.
(c) Description of the new method in detail.
(d) Diagram of the workplace layout and sketches of special tools, jigs or fixtures required.
6. Install
This step is the most difficult stage in method study. Here the active support of both management
and trade union is required. Here the work study man requires skill in getting along with other
people and winning their trust. Instal stage consists of
(a) Gaining acceptance of the change by supervisor.
(b) Getting approval of management.
(c) Gaining the acceptance of change by workers and trade unions.
(d) Giving training to operators in the new method.
(e) To be in close contact with the progress of the job until it is satisfactorily executed.
Rearrangement of layout etc: The machines are rearranged as per the layout suggested in the new
method. New tools and devices are introduced as per the new method. The working conditions like
lighting, ventilation etc. are improved as required in the new method.
Training of workers and rehearsal: The workers are given training in the new method; i.e., in the
new tools and devices. The trial run (rehearsal) of the new method is done. This is done to check the
success of the new method. If there is any problem, modifications are made. Meeting with the
supervisor is held daily to discuss the progress.
7. Maintain
The work study man must see that the new method introduced is followed. The workers after sometime
may slip back to the old methods. This should not be allowed. The new method may have defects.
There may be difficulties also. This should be rectified in time by the work study man.
Periodical review is made. The reactions and suggestions from workers and supervisors are
noted. This may lead to further improvement. The differences between the new written standard
practice and the actual practice are found out. Reasons for variations are analysed. Changes due
to valid reasons are accepted. The instructions are suitably modified.
1.5 CHARTS AND DIAGRAMS USED IN METHOD STUDY (TOOLS AND
TECHNIQUES)
As explained earlier, the following charts and diagrams are used in method study.
1. Operation process chart (or) Outline process chart.
2. Flow process chart.
(a) Material type
(b) Operator type
(c) Equipment type
3. Two-handed process chart. (or) Left hand-Right hand chart
4. Multiple activity chart.
5. Flow diagram.
6. String diagram.

26.
Work Study
9
1.5.1 Process Chart Symbols
The recording of the facts about the job in a process chart is done by using standard symbols.
Using of symbols in recording the activities is much easier than writing down the facts about the
job. Symbols are very convenient and widely understood type of short hand. They save a lot of
writing and indicate clearly what is happening.
1. Operation
A large circle indicates operation. An operation takes place when there is a change in physical or
chemical characteristics of an object. An assembly or disassembly is also an operation.
When information is given or received or when planning or calculating takes place it is also
called operation.
Example 1.1
Reducing the diameter of an object in a lathe. Hardening the surface of an object by heat
treatment.
2. Inspection
A square indicates inspection. Inspection is checking an object for its quality, quantity or identifications.
Example 1.2
Checking the diameter of a rod. Counting the number of products produced.
3. Transport
An arrow indicates transport. This refers to the movement of an object or operator or equipment
from one place to another. When the movement takes place during an operation, it is not called
transport.
Example 1.3
Moving the material by a trolley
Operator going to the stores to get some tool.
Operation
Inspection
Transport
Delay
Storage
Combined
activity
Fig. 1.1: Process chart symbols
4. Delay or temporary storage
A large capital letter D indicates delay. This is also called as temporary storage. Delay occurs
when an object or operator is waiting for the next activity.
Example 1.4
An operator waiting to get a tool in the stores. Work pieces stocked near the machine before
the next operation.

27.
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Process Planning and Cost Estimation
5. Permanent storage
An equilateral triangle standing on its vertex represents storage. Storage takes place when an object
is stored and protected against unauthorized removal.
Example 1.5
Raw material in the store room.
6. Combined activity
When two activities take place at the same time or done by the same operator or at the same
place, the two symbols of activities are combined.
Example 1.6
Reading and recording a pressure gauge. Here a circle inside a square represents the combined
activity of operation and inspection.
1.5.2 Operation Process Chart
An operation process chart is a graphic representation of the sequence of all operations and
inspections taking place in a process. It is also known as outline process chart. It gives a bird’s
eye view of the overall activities. Entry points of all material are noted in the chart.
An example of operation process chart is shown in the figure 1.2. Here the process of
manufacture of electric motor is shown.
Fig. 1.2: Operation process chart

28.
Work Study
11
The conventions followed in preparing the chart are
1. Write title at the top of the chart.
2. Begin the chart from the right hand side top corner.
3. Represent the main component at the right extreme.
4. Represent the sequence of operations and inspections by their symbols. Connect them by
vertical flow lines.
5. Record the brief description of the activity to the right side of the symbols.
6. Note down the time for each activity to the left of the symbol.
7. Number all operations in one serial order. Start from the right hand top (from number 1).
8. Similarly number all inspections in another serial order (starting from 1).
9. Continue numbering, till the entry of the second component.
10. Show the entry of purchased parts by horizontal lines.
1.5.3 Flow Process Chart
A flow process chart is a graphical representation of the sequence of all the activities (operation,
inspection, transport, delay and storage) taking place in a process. Process chart symbols are used
here to represent the activities. There are three types of flow process charts. They are
1. Man type flow process chart
This flow process chart records what the worker does.
2. Material type flow process chart
This flow process chart records how the material is handled or treated.
3. Equipment type flow process chart
This flow process chart records how the equipment or machine is used.
Example 1.7
The activities of a stenographer in preparation of a letter are recorded in the operator type
flow process chart shown in figure 1.3.
Chart No.
: 001
Job
: Typing A letter
Chart begins : Steno in her seat
Method
: Present/Proposed
Sl. No.
Description of the activities
Date :
Charted by:
…………………
Chart ends-putting the typed letter in the way
Distance
Time in Sec.
Symbols
O
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Steno in her seat
Hears the bell
Goes to manager’s room
Takes down dictation
Returns to her seat
Prepares typewriter
Types the letter
Checks the matter
Goes to manager’s room
Waits till the manager signs
Returns to her seat
Types envelope
Puts the letter inside envelope
Puts the envelope in dispatch tray
6m
6m
6m
6m
-
3
10
120
10
15
150
40
10
20
10
20
5
5
Fig. 1.3: Flow process chart—operator type
⇒ D ∇
Remarks

29.
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Process Planning and Cost Estimation
The chart records the activities of the steno. Here, the manager calls the steno and dictates a
letter. The steno takes notes of the letter, types it, gets the signature of the manager and sends it
for dispatching. These activities are shown in the chart. This is operator type flow process chart.
Considering the message in the letter as material, we can prepare the material type flow process
chart.
Similarly, considering the type writer as the equipment, we can prepare the equipment type
flow process chart.
General guidelines for making a flow process chart
1.
2.
3.
4.
5.
The details must be obtained by direct observation—charts must not be based on memory.
All the facts must be correctly recorded.
No assumptions should be made.
Make it easy for future reference.
All charts must have the following details:
(a) Name of the product, material or equipment that is observed.
(b) Starting point and ending point.
(c) The location where the activities take place.
(d) The chart reference number, sheet number and number of total sheets.
(e) Key to the symbols used must be stated.
1.5.4 Two-Handed Process Chart (or) Right Hand, Left Hand Chart
It is the process chart in which the activities of two hands of the operator are recorded.
It shows whether the two hands of the operator are idle or moving in relation to one another,
in a timescale. That is, we know from the chart what the two hands are doing at any given moment
of time.
The two-handed process chart is generally used for repetitive operations. Here one complete
cycle of work activities is recorded. Recording is done in more detail than ordinary flow process
chart. What is shown as a single activity in a flow process chart is broken into small elemental
activities and recorded.
Two-handed process chart generally use the same symbols as other process charts. But the
definitions of symbols are slightly different. This is because we record the activities of hands only.
Operation: Represents the activities grasp, position, use, release etc. of a tool, component or
material.
Transport: Represents the movement of the hand or limb to or from the work or a tool or material.
Delay: Refers to the time when the hand or limb is idle.
Storage (Hold): The term ‘hold’ is used here instead of storage. This refers to the time when the
work is held by hand.
The activity ‘inspection’ by hand is considered as an operation. Hence, the symbol for inspection
is not used in this chart.
Two-handed process chart can be used for assembly, machining and clerical jobs.
General guidelines for preparing the chart
1. Provide all information about the job in the chart.
2. Study the operation cycle a few times before starting to record.
3. Record one hand at a time.

30.
Work Study
13
4. First record the activities of the hand which starts the work first.
5. Do not combine the different activities like operations, transport etc.
Example 1.8
Example of a two-handed process chart is shown in figure 1.4. Here the assembly of a nut
and washer over a bolt is recorded.
The work place layout is shown in the right hand corner. The activities of left hand are recorded
at left half of the chart. The activities of the right hand are recorded at the right half of the chart.
Job
Chart begins
Chart ends
Chart
Operator
:
:
:
:
:
Assembly of washer and nut to a bolt
Both hands free before assembly
Both hands free after assembly
Existing method/Proposed method
Assembly
Bolt
Washer
Date
:
Chart No :
Left hand
Operator
Right hand
Sl. No. Description of the activities
Symbols
Sl. No. Description of the activities
O ⇒ ∇
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Nut
To the bolt tray
Picks up one bolt
Returns to original position
Holding the bolt
Idle
Idle
Idle
Idle
To the assembly tray
Puts the bolt in the tray
Returns to the original position
Symbols
O ⇒ ∇
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
To the washer tray
Picks up one washer
Returns to the initial position
Assembles washer over bolt
To the nut tray
Picks up one nut
Returns to initial position
Assemble nut to the bolt
Idle
Idle
Idle
Fig. 1.4: Two-handed process chart
The horizontal lines represent the time scale. Activities of left hand and right hand shown in
the same line occur at the same moment.
Summary of the number of each activity can be tabulated at the bottom of the chart.
The chart is first drawn for the existing method. This chart is analysed and if it is found that
one hand is over loaded than the other, modification are done in the layout of the workplace or in
the sequence of activities. Then a new chart is made for the proposed cycle.
1.5.5 Man-Machine Chart
A man-machine chart is a chart in which the activities of more than one worker or machine are
recorded. Activities are recorded on a common time scale to show the inter-relationship. It is also
known as multiple activity chart.
It is used when a worker operates a number of machines at a time. It is also used when a
number of workers jointly do a job.
Activities of workers or machines are recorded in separate vertical columns (bars) with a
horizontal time scale. The chart shows the idle time of the worker or machine during the process.

31.
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Process Planning and Cost Estimation
By carefully analyzing the chart, we can rearrange the activities. Work load is evenly distributed
among the workers or machines by this the idle time of worker or machine is reduced.
Multiple activity chart is very useful in planning team work in production or maintenance. Using
the chart we can find out the correct number of machines that a worker can operate at a time.
We can also find out the exact number of workers needed to do a job jointly.
To record the time, ordinary wrist watch or stop watch is used. High accuracy is not needed.
Man-machine chart is a type of multiple activity chart. Here, the activities of a number of
machines are recorded.
An example of man-machine chart is shown in figure 1.5. Here one operator two semi-automatic
machines simultaneously. The activities of the operator is recorded in a separate vertical column.
The activities of the two machines are recorded in two separate vertical columns. The different
activities like loading, machining and unloading are represented by different symbols. Blank space
shows the idle time.
Man-machine chart–present method
Job: One operator operating two machines
Operator:
Activity
MCI MCII Symbol
Charted by:
Loading
1mt 1mt
Date:
Machining 8mt 5mt
Unloading 1mt 1mt
Time
in mts
1
Operator
M/C I
M/C II
2
3
4
5
Idle
6
7
8
9
10
11
12
Idle
Fig. 1.5: Man-machine chart
1.5.6
Flow Diagram
In any production shop, repair shop or any other department, there are movements of men and
material from one place to another. Process charts indicate the sequence of activities. They do not
show the frequent movements of men and material. If these movement are minimized, a lot of

32.
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15
savings can be achieved in cost and effort. If the path of movement of material is not frequent and
simple, a flow diagram is used for recording the movement.
A flow diagram is a diagram which is drawn to scale. The relative position of machineries,
gang ways, material handling equipment etc. are drawn first. Then the path followed by men or
material is marked on the diagram. Different movements can be marked in different colours. Process
symbols are added to the diagram to identify the different activities at different work centres.
Flow Diagram–Exiting Method
Job: Raw material from stores machined
and finished components stoked in stores.
Diagram prepared by ________ Date ______
Scale:
Mill
Drill
Slotting
Shaper
D
Lathe
R.M.S tores
Inspection
Finis hed
Stores
Fig. 1.6: Flow diagram
The flow diagram are used for the following purposes:
1. To remove unwanted material movement.
2. To remove back tracking.
3. To avoid traffic congestion.
4. To improve the plant layout.
Conventions adopted are
1. Heading and description of the process should be given at the top of the diagram.
2. Other informations like location, name of the shop, name of the person drawing the diagram
are also given.

33.
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Process Planning and Cost Estimation
3. The path followed by the material is shown by a flow line.
4. Direction of movement is shown by small arrows along the flow lines.
5. The different activities are represented by the symbols on the flow lines. (Same symbols
used in flow process chart are used here).
6. If more than one product is to be shown in the diagram different colours are used for each
path.
Examples of a flow diagram of the existing arrangements is shown in the figure 1.6. The path
of movement of material in the work floor is shown. The different activities done on the material
are shown using symbols.
In this existing method, the movement of the material is more. By interchanging the positions
of drilling and milling machines, the material movement can be reduced.
1.5.7 String Diagram
String diagram
Job: Study of movement of a machinist
prepared by __________ Date ________
Scale:
Machine
Machine
Machine
Inspection
Toilet
Tool
room
Stores
Supervisor
Fig. 1.7: String diagram
We make use of flow diagram for recording the movement of men or material when the
movement is simple and the path is almost fixed. But when the paths are many and are repetitive,
it may not be possible to record them in a flow diagram. Here a string diagram is used.
String diagram is a scaled plan of the shop. Location of machines and various facilities are
drawn to scale in a drawing sheet. Pins are fixed at the various work centres in the drawing sheet.
A continuous coloured thread or string is taken round the pins where the material or worker moves
during the process.
Constructions
1. Draw the layout of the shop to scale in a drawing sheet.

34.
Work Study
17
2.
3.
4.
5.
Mark the various work centres like machines, stores, work bench etc. in the diagram.
Hold the drawing sheet on a soft board and fix pins at the work centres.
Tie one end of a coloured string to the work centre from which the movement starts.
Follow the path of the worker to different work centre and accordingly take the thread to
different points on the drawing board.
6. At the end of the session note down the number of movements from one work centre to
another.
7. Remove the string and measure the total length of the string. Multiply by the scale and
get the actual distance of movement.
Applications
1.
2.
3.
4.
5.
It is used for recording the complex movements of material or men.
Back tracking, congestion, bottlenecks, under utilized paths are easily found out.
It is used to check whether the work station is correctly located.
Used to record irregular movements.
Used to find out the most economical route.
1.6 WORK MEASUREMENT
Work measurement is a technique to establish the time required for a qualified worker to carry out
a specified job at a defined level of performance.
Objectives of work measurement
1.
2.
3.
4.
To reduce or eliminate non-productive time.
To fix the standard time for doing a job.
To develop standard data for future reference.
To improve methods.
Uses of work measurements
1. To compare the efficiency of alternate methods. When two or more methods are available
for doing the same job, the time for each method is found out by work measurement. The
method which takes minimum time is selected.
2. Standard time is used as a basis for wage incentive schemes.
3. It helps for the estimation of cost. Knowing the time standards, it is possible to work out
the cost of the product. This helps to quote rates for tenders.
4. It helps to plan the workload of man and machine.
5. It helps to determine the requirement of men and machine. When we know the time to
produce one piece and also the quantity to be produced, it is easy to calculate the total
requirement of men and machines.
6. It helps in better production control. Time standards help accurate scheduling. So the
production control can be done efficiently.
7. It helps to control the cost of production. With the help of time standards, the cost of
production can be worked out. This cost is used as a basis for control.
8. It helps to fix the delivery date to the customer. By knowing the standard time we will be
able to calculate the time required for manufacturing the required quantity of products.

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Process Planning and Cost Estimation
1.7 TECHNIQUES OF WORK MEASUREMENT
The different techniques used in work measurement are
1. Stop watch time study.
2. Production study.
3. Work sampling or Ratio delay study.
4. Synthesis from standard data.
5. Analytical estimating.
6. Predetermined motion time system.
1.7.1 Stop Watch Time Study
Stop watch time study is one of the techniques of work measurement commonly used. Here we
make use of a stop watch for measuring the time.
Procedure for conducting stop watch time study
The following procedure is followed in conducting stop watch time study:
1. Selecting the job.
2. Recording the specifications.
3. Breaking operation into elements.
4. Examining each element.
5. Measuring using stop watch.
6. Assessing the rating factor.
7. Calculating the basic time.
8. Determining the allowances.
9. Compiling the standard time.
1. Selection of job
Time study is always done after method study. Under the following situations, a job is selected for
time study:
1. A new job, new component or a new operation.
2. When new time standard is required.
3. To check the correctness of the existing time standard.
4. When the cost of operation is found to be high.
5. Before introducing an incentive scheme.
6. When two methods are to be compared.
2. Record
The following informations are recorded
1. About the product-name, product-number, specification.
2. About the machine, equipment and tools.
3. About the working condition-temperature-humidity-lighting etc. These informations are used
when deciding about the allowances.
4. About the operator name-experience-age etc. This is needed for rating the operator.
3. Break down operation into elements
Each operation is divided into a number of elements. This is done for easy observation and accurate
measurement. The elements are grouped as constant element, variable element, occasional element,
man element, machine element etc.

36.
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19
4. Examine each element
The elements are examined to find out whether they are effective or wasteful. Elements are also
examined whether they are done in the correct method.
5. Measure using a stop watch
The time taken for each element is measured using a stop watch. There are two methods of
measuring. viz., Fly back method and Cumulative method. Cumulative method is preferable.
The time measured from the stop watch is known as observed time. Time for various groups
of elements should be recorded separately.
This measurement has to be done for a number of times. The number of observations depend
upon the type of operation, the accuracy required and time for one cycle.
6. Assess the rating factor
Rating is the measure of efficiency of a worker. The operator’s rating is found out by comparing
his speed of work with standard performance. The rating of an operator is decided by the work
study man in consultation with the supervisor. The standard rating is taken as 100. If the operator
is found to be slow, his rating is less than 100 say 90. If the operator is above average, his rating
is more than 100, say 120.
7. Calculate the basic time
Basic time is calculated as follows by applying rating factor
Basic time = Observed time ×
BT = OT ×
Operator rating
Standard rating
OR
SR
8. Determine the allowance
A worker cannot work all the day continuously. He will require time for rest going for toilet, drinking
water etc. Unavoidable delays may occur because of tool breakage etc. So some extra time is
added to the basic time. The extra time is known as allowance.
9. Compile the standard time
The standard time is the sum of basic time and allowances. The standard time is also known as
allowed time.
1.7.1.1 Breaking a Job into Elements
It is necessary to break down a task (job) into elements for the following reasons:
1. To separate productive time and unproductive time.
2. To assess the rating of the worker more accurately.
3. To identify the different types of elements and to measure their timings separately.
4. To determine the fatigue allowance accurately.
5. To prepare a detailed work specification.
6. To fix standard time for repetitive elements (such as switch on or switch off of machine).

37.
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Process Planning and Cost Estimation
Classification of elements
1. Repetitive elements
It is an element which occurs in every work cycle of the job.
Example 1.9
Loading the machine, locating a job in a fixture.
2. Constant element
It is an element for which the basic time remains constant whenever it is performed.
Example 1.10
Switching on the machine, switching off the machine.
3. Variable element
It is an element for which the basic time varies depending on the characteristics of the product,
equipment or process.
Example 1.11
Saving a log of wood-time changes with diameter or the work.
4. Occasional element
It is an element which does not occur in every work cycle of the job. It may occur at regular or
irregular intervals.
Example 1.12
Regrinding of tools, re-setting of tools.
5. Foreign element
It is an element which is not a part of the job.
Example 1.13
Cleaning a job that is to be machined.
6. Manual element
It is an element performed by the worker.
Example 1.14
Cleaning the machine, loading the machine.
7. Machine element
It is the element automatically performed by a power driven machine.
Example 1.15
Turning in a lathe using automatic feed.
General rules to be followed in breaking down a task into elements
1. Element should have a definite beginning and ending.
2. An element should be as short as possible so that it can be conveniently timed.
The shortest element that can be timed using a stop watch is 0.04 mt.
3. Manual elements and machine elements should be separately timed.
4. Constant element should be separated from variable elements.
5. Occasional and foreign elements should be timed separately.

38.
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21
1.7.1.2 Measuring Time with a Stop Watch
There are two methods of timing using a stop watch. They are
1. Fly back or Snap back method.
2. Continuous or Cumulative method.
1. Fly back method
Here the stop watch is started at the beginning of the first element. At the end of the element the
reading is noted in the study sheet (in the WR column). At the same time, the stop watch hand is
snapped back to zero. This is done by pressing down the knob, immediately the knob is released.
The hand starts moving from zero for timing the next element. In this way the timing for each
element is found out. This is called observed time (O.T.)
.
2. Continuous method
Here the stop watch is started at the beginning of the first element. The watch runs continuously
throughout the study. At the end of each element the watch readings are recorded on the study
sheet. The time for each element is calculated by successive subtraction. The final reading of the
stop watch gives the total time. This is the observed time (O.T.).
Comparison of fly back and continuous method
Sl. No.
1.
2.
3.
4.
Fly back
Element times are obtained directly. No
successive subtraction needed.
Time is lost in snapping back of watch.
So error is introduced.
Short elements may be missed.
Continuous
Elemental times obtained only by
successive subtractions.
No time is lost in snapping back.
No such error and hence study is accurate.
Even if a short element is missed, its time
will get included in the total time.
Note: As we find that the continuous method is accurate, it is preferable.
1.8 RATING FACTOR
Rating is the assessment of the rate of working of the operator by the work study man. The work
study man does this rating based upon his idea of standard performance.
Standard performance is the rate of output which a qualified worker will give on an average.
The worker gives this output willingly without much strain.
Bench mark for standard rating. The motion of the operator with standard rating will be
equivalent to the speed of motion of the limbs of a man of average physique when
1. Walking without a load in a straight line on a level ground at a speed of 6.4 km per hour.
2. Distributing a pack of 52 playing cards at the four corners of a square table of 1 foot side
in 0.375 mts.
Rating scales
The different rating scale universally adapted are
1. 60–80 scale.
2. 75–100 scale.
3. 100–133 scale.
In the above scales, the lower figures 60,75 and 100 correspond to standard performance of
the workers, when the worker is given a time rate of pay. No incentives are given. The higher
figures 80,100 and 133 correspond to the standard performance of the workers, when they are
motivated by incentives. Among the above scales 75–100 scale is universally adopted.

39.
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Process Planning and Cost Estimation
Applying rating factor
Here, normally we adopt the scale of 75–100. When the performance of the operator is above
average, he is given a rating of more than 100, say 110, 115 etc.
If the performance of the operator is below average, he is given a rating of less than 100, say
85, 90 etc.
If the performance of the operator is average, he is given a rating of 100
The rating number should be always rounded of to the nearest multiples of five on the scale.
1.9 CALCULATION OF BASIC TIME
Basic time is the time taken by an operator of standard performance (rating of 100).
A man whose work is observed, may be a slow worker or a fast worker. His rating may be
less than 100 or above 100. The observed time cannot be taken as the basic time. Here the rating
factor is applied and basic time is calculated as follows.
Operator rating
Basic time = Observed time ×
Standard rating
For example, assume that observed time for an operation is 0.7 mts. The rating of the operator
is found to be 120.
120
The Basic Time or Normal Time = 0.7 ×
= 0.84 mts.
100
Performance below average
O.T.
B.T or N.T.
Rating
Performance above average
Fig. 1.8: Basic time calculation
1.10 ALLOWANCES
It is not possible for a worker to do his job continuously without any break. There are many
interruptions (stoppage of work) taking place. Extra time is added to the basic time to compensate
this interruption. This extra time given is known as allowance.
Generally interruption occur due to the following
1. Personal factors.
Going for drinking water, toilet etc.
2. Nature of work.
Taking rest after hard work
3. Other factors.
Tool breakage, listening to supervisor etc.

40.
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23
Various types of allowance are
1. Rest and personal allowance.
4. Special allowance.
2. Process allowance.
5. Policy allowance.
3. Contingency allowance.
1. Rest and personal allowance
This is the allowance given for the personal needs of the worker viz., going to toilet, drinking
water, taking rest etc. Personal allowance given, depends upon the working condition and nature
of work. For example heavy work at high temperature (working near furnace) needs more
allowance. This allowance is also known as relaxation allowance.
2. Process allowance
This is also known as unavoidable delay allowance. A worker working in an incentive system
may have to be idle due to unavoidable delays. This delay may be due to process, machine operation,
waiting for work, waiting for material etc. To compensate this delay, process allowance is given.
3. Contingency allowance
In a shop, there may be small delays due to
1. Waiting for the inspector.
2. Consulting the supervisor.
3. Obtaining special tools etc.
These delays are of very short duration. The allowance given to compensate these delays is
called contingency allowance. Generally 5% of basic time is given as contingency allowance.
4. Special allowance
In a shop, some activities take place occasionally. These activities will not be part of the
production cycle. But these are necessary for production work. Example of these activities are
1. Tool re-setting.
2. Cleaning.
3. Tool maintenance.
4. Shut down.
For these activities an allowances known as special allowance is given.
5. Policy allowance
This is an allowance given according to the policy of the management. It is not included for
calculating the standard time. This is an extra benefit given by the management to the workers.
This allowance is given to increase the workers, earnings.
1.11 CALCULATION OF STANDARD TIME
Standard time or allowed time is the total time in which a job should be completed at standard
performance. It is the sum of normal time (basic time) and allowances. Policy allowance is not
included.
Standard time is worked out in a stop watch time study in the following manner.
Observed time
This is the actual time observed by using a stop watch. The observed time of an operation is the
total of the elemental times.
The time study for the same job is conducted for a number of times. The average of the
observed times is calculated.

41.
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Process Planning and Cost Estimation
Basic or normal time
Basic time is the time taken by a worker with standard performance. Basic time is calculated from
the observed time by applying the rating factor.
Basic time or
Rating of the operator
Normal time = Observed time ×
Standard rating (100)
O.T.
R.F
R.A
PR.A C.A
P.A
Rating
Standard time
(or) Allowed time
OT
RF
RA
–
–
–
Observed time
Rating factor
Rest allowance
PRA –
CA –
PA –
Process allowance
Contingency allowance
Policy allowance
Fig. 1.9
Allowed time or standard time
The standard time is obtained by adding the following allowances with the basic or normal time.
1. Rest and personal allowance or relaxation allowance.
2. Process allowance or unavoidable delay allowance.
3. Contingency allowance.
4. Special allowance.
Policy allowance may be added to the standard time if the management wants.
1.12 PRODUCTION STUDY
By stop watch time, study time standards are set. But there may be complaints from the operator
that the time given for a job is not sufficient. So it is necessary to check the original time study
production study is a technique of work measurement to check accuracy of the original time study.
This study is done to find the time delay due to occasional elements. These elements may occur at
irregular intervals. Example: Tool grinding, setting tools etc. There are chances of missing these
elements in the stop watch time study. Production study is conducted for a longer period—at least
for half a day or one shift.
Uses of production study
1.
2.
3.
4.
5.
To check the accuracy of time standards.
To make sure that all the ineffective elements are included in the time study.
To observe the waiting time and other delays of operator.
To get the data for working out the contingency allowance.
When the output goes down, this study is conducted to find out the reasons for it.
Procedure for production study
Production study is conducted just like ordinary stop watch time study. But here the time for
occasional elements alone are observed. This is done for a long period, say for 1 shift. Repetitive

42.
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25
or routine activities are not timed. The timings for occasional elements are compared with the
allowance already included in the standard time.
1. Error in the original time study.
2. Changes in conditions of material, tools and equipments.
3. Inexperienced operator.
4. Changes in the method of doing work.
5. Changes in the working condition.
6. Changes in the layout.
7. Incorrect machine speed.
The exact reasons for the error are found out and rectified.
1.13 RATIO DELAY STUDY
This study is also known as work sampling or activity sampling. Here the ratio of the delay time
and working time to the total time of an activity is found out. This is done by random (irregular)
observations. This study is applied to
1. Long cycle operations.
2. Activities where time study is not possible.
Example 1.16
Office work, supervising work, activities in stores and warehouses etc.
3. Estimate the percentage utilization of machine tools, cranes, trucks etc.,
4. Estimate the percentage idle time of men in group activities.
5. Estimate the standard time for manual task.
Procedure
1. Define the objectives
Decide the element to be studied. State whether idle time of men or machine is to be studied.
Decide the shop floor. Decide the nature of activity—Indicate the location of men and machine.
2. Select the sampling technique
Decide the number of observations to be made—Decide the length of time of observations—
Referring to the random number tables, decide the schedule of observations i.e., at what time each
observation has to be made.
3. Prepare the forms for recording
Prepare the form as shown in the figure 1.10.
Date
Observer
Number of observation : 150
Study No.:
Total
Percentage
120
80-0
llll llll llll llll llll llll llll llll llll llll
Machine Running
llll llll llll llll llll llll llll llll llll llll
llll llll llll llll
Repairs
llll
3
2-0
Machine Supplies
llll llll llll ll
12
8-0
Idle Personal
llll l
6
4-0
Idle
llll llll
9
6-0
Fig. 1.10

43.
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Process Planning and Cost Estimation
4. Make observations
Visit the work spot as per this timing noted in the form. Note down whether men or machine is
working or idle in the form.
5. Process the data
Analyse the observed data and calculate the percentage utilization or idle time for men or machine.
Example 1.17
Number of observations made – 150
Number of times m/c found working – 120
Number of times m/c found idle – 30
% utilization of machine – (120 ÷150) × 100 = 80%
% idle time of machine – (30 ÷ 150) × 100 = 20%
Advantages
1. Activities which cannot be studied by stop watch time study can be observed.
2. Cost of the study is less. A single study man can observe several machines and operations.
3. This study is not a continuous study. So lesser time is spend on the study.
4. The study will not interrupt the production.
5. The operators do not feel that they are closely watched by study man. So they work freely.
6. Trained study man is not required.
7. Calculation is easy.
8. No equipment—Stop watch or other devices are not needed.
Limitations
1. This is economical only when the study is made in a wide area. i.e., group of machines or
group of operators.
2. This is not suitable for short cycle repetitive operations.
3. This is not a detailed study.
1.14 SYNTHESIS FROM STANDARD DATA
Synthesis is a work measurement technique to work out standard time for a job by totaling the
elemental times already obtained from previous time studies.
Many operators in an industry have several common elements. Example: starting the machine,
stopping the machine etc. Whenever these activities occur, they take the same duration of time.
These elements are called constant elements. Time for some elements vary proportionately with
the speed, feed, length of cut etc. in machining operation. These elements are known as variable
elements.
Time for all these constant elements and variable elements are collected from the time studies
previously made. These are stored in a file. This is called time standard data bank. Data bank
contains data in the form of
1. Tabulated standard time for constant elements.
2. Charts and graphs.
3. Formulae etc.
So, the time for any operation can be worked out without actually making the time study.

44.
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27
Procedure
Material: M.S; cutting speed 25m / mt
D1
T1
D2
D3
Time in mts
T2
O
e1
e2
Length of cut in mm
Fig. 1.11
1. Break the operation into elements.
The operations are broken into a number of elements. Variable elements and constant are
separated.
2. Collect the elemental time for constant elements from the standard data bank.
3. For variable elements, the elemental time can be found out by using the charts and graphs.
An example of graph taken from a data bank is given in figure 1.11. In the graph, time for
machining is plotted in Y axis. The length of cut is plotted in X axis. The graph, the time for machining
various lengths of cut for different diameters for example, for the job with a diameter D1, the
machining time for a length of cut I1 is T1. Similarly, for a job with a diameter D2, the machining
time for a length of cut I2 is T2.
4. Add all the elemental times for constant and variable elements. With this, add the allowances
such as rest allowance, interference allowance, process allowance, special allowance,
contingency allowance etc. to get the standard time. The time for various allowance are
also available in the standard data bank.
Advantages
1.
2.
3.
4.
The time calculated using standard data is more accurate than the stop watch time study.
The process is very quick.
It is a cheaper method.
It is used for estimating the cost of production before actually producing. It is used to offer
quotation.
5. It is useful for planning team work such as assembly work.
Limitations
1. Collection of data bank is a costly affair.
2. It is applied only in larger industries.
3. The data bank should be updated periodically.

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Process Planning and Cost Estimation
1.15 ANALYTICAL ESTIMATING
Setting the time standards for long and non-repetitive operations by stop watch method are
uneconomical.
Analytical estimating technique determines the time values for such jobs either by using the
synthetic data or on the basic of the past experience of the estimator when no synthetic or standard
data is available. In order to produce accurate results the estimator must have sufficient experience
of estimating, motion study, time study and the use of synthesized time standards.
1.15.1 Procedure
The various procedural steps involved in analytical estimating are:
1. Select the estimator.
2. Find out job details which include job dimensions, standard procedure and especially the
job conditions, i.e., poor illumination, high temperatures, hazardous environments, availability
of special jigs, fixtures or toolings, condition of materials, etc.
3. Break the job into constituent elements.
4. Select the time values for as many elements possible from the data bank (i.e., synthetic
data).
5. To the remaining elements for which no synthetic data is available, usually the estimator
gives suitable time values from his past knowledge and experience.
6. Add 4 and 5 and this is the total basic time at a 100% rating.
7. Add to 6 appropriate Blanket Relaxation allowance. In analytical estimating, relaxation
allowance is not added to individual elements, rather a blanket R.A. depending upon the
type of job and job conditions. This is calculated as a percentage (10 to 20%) of the total
basic time and is added to the total basic time.
8. Any additional allowances if applicable may be added to 7 in order to arrive standard time
for the given job.
1.15.2 Advantages
1.
2.
3.
4.
It possesses almost the same advantages as enjoyed by synthesis from standard data.
It aids in planning and scheduling.
It provides a basis for rate fixing for non-repetitive works in industries.
It improves labour control.
1.15.3 Limitations
The estimate will not be accurate.
1.15.4 Application
Analytical estimating is used.
1. For non-repetitive jobs, jobs involved long cycle times and the jobs having elements of variable
nature.
2. In repair work,
• Tool rooms.
• Job production.

46.
Work Study
•
•
•
•
•
•
29
Maintenance work.
Inspection work.
Erection work.
Engineering construction.
One time large projects, and
Office routines etc.
1.16 PREDETERMINED MOTION TIME SYSTEM (PMTS)
1.16.1 Definition
PMTS is a work measurement technique where by times, established for basic human motions
(classified according to the nature of the motion and the conditions under which it is made) are
used to build up the time for a job at a defined level of performance. Few well-known systems
using this concept are
1. M.T.M. : Method Time Measurement.
2. W.F.S. : Work Factor System.
3. M.T.A. : Motion Time Analysis.
4. D.M.T. : Dimensional Motion Times.
5. B.M.T. : Basic Motion Times.
Out of these, MTM technique is widely used.
1.16.2 Method Time Measurement (M.T.M.)
M.T.M. analyses an industrial job into the basic human movements required to do the same. From
the tables of these basic motions, depending upon the kind of motion, and conditions under which
it is made, predetermined time values are given to each motion. When all such times are added up,
it provides the normal time for the job. Standard time can be found by adding suitable allowances.
According to M.T.M. the various classification of motions are
1. Reach – R.
2. Move – M.
3. Turn and Apply Pressure – T and AP.
4. Grasp – G.
5. Position – P.
6. Release – RL.
7. Disengage – D.
8. Eye travel time and eye focus – ET and EF.
9. Body, leg and foot motions and,
10. Simultaneous motions.
A table is provided for each motion. Depending upon different characteristics of a motion, the
time can be read from the table.
1.16.3 Table Preparation
Groups of average workmen (by age, physical attributes, temperament) were selected and placed
under laboratory conditions (average heat, light atmospheric conditions etc.). These work men were

47.
30
Process Planning and Cost Estimation
made to perform a wide variety of motions which were filmed with a cine camera at 16 frames
per sec. These films were later exhibited using a constant speed projector to a group of highly
qualified industrial engineers who rated the films.
The net result of these experiments were the development of MTM tables for the time values
for all the basic motions performed by a human body. There are 10 MTM tables, 9 of which provide
time for various types of motions.
Unit time in the tables is one hundred, thousandth of an hour (0.00001 hr) and is referred to
one time measurement unit (TMU)
1. T.M.U. =
1
= 1 × 10−5 hr
100 × 1000
= 0.00001 hr = 0.0006 minutes.
The conversion system of TMU’s into hours, minutes or seconds is as under
1 hour = 1,00,000 TMU’s
1 minute = 1,667 TMU’s
1 second = 28 TMU’s
1 TMU = 0.00001 hrs.
= 0.00006 minutes.
1.16.4 Advantages of MTM
1.
2.
3.
4.
Time standard for a job can be arrived at without going to the place of work.
Alternative methods are compared easily.
It helps in tool and product design.
It eliminates in accuracies associated with stop watch time study.
1.16.5 Limitations
MTM can deal only with manual motions of an operation.
1.17 ERGONOMICS
Ergons means ‘work’ and Nomos means ‘Natural laws’. Ergonomics or its American equivalent
‘Human Engineering may be defined as the scientific study of the relationship between man and
his working environments.
Ergonomics implies ‘Fitting the job to the worker’. Ergonomics combines the knowledge of a
psychologist, physiologist, anatomist, engineer, anthropologist and a biometrician.
1.17.1 Objectives
The objectives of the study of ergonomics is to optimize the integration of man and machine in
order to increase work rate and accuracy. It involves
1. The design of a work place befitting the needs and requirements of the worker.
2. The design of equipment, machinery and controls in such a manner so as to minimize mental
and physical strain on the worker thereby increasing the efficiency, and
3. The design of a conductive environment for executing the task most effectively.
Both work study and Ergonomics are complementary and try to fit the job to the workers;
however Ergonomics adequately takes care of factors governing physical and mental strains.

48.
Work Study
31
1.17.2 Applications
In practice, ergonomics has been applied to a number of areas as discussed below
1. Working environments
2. The work place, and 3. Other areas.
1. Working environments
(a) The environment aspect includes considerations regarding light, climatic conditions (i.e.,
temperature, humidity and fresh air circulation), noise, bad odour, smokes, fumes, etc., which
affect the health and efficiency of a worker.
(b) Day light should be reinforced with artificial lights, depending upon the nature of work.
(c) The environment should be well-ventilated and comfortable.
(d) Dust and fume collectors should preferably be attached with the equipments giving rise to
them.
(e) Glares and reflections coming from glazed and polished surfaces should be avoided.
(f) For better perception, different parts or sub-systems of equipment should be coloured
suitably. Colours also add to the sense of pleasure.
(g) Excessive contrast, owing of colour or badly located windows, etc., should be eluded.
(h) Noise, no doubt distracts the attention (thoughts, mind) but if it is slow and continuous,
workers become habituated to it. When the noise is high pitched, intermittent or sudden, it
is more dangerous and needs to be dampened by isolating the place of noise and through
the use of sound absorbing materials.
2. Work place layout
Design considerations
(a) Materials and tools should be available at their predetermined places and close to the worker.
(b) Tools and materials should preferably be located in the order in which they will be used.
(c) The supply of materials or parts, if similar work is to be done by each hand, should be
duplicated. That is materials or parts to be assembled by right hand should be kept on right
hand side and those to be assembled by the left hand should be kept on left hand side.
(d) Gravity should be employed, wherever possible, to make raw materials reach the operator
and to deliver material at its destination (e.g., dropping material through a chute).
(e) Height of the chair and work bench should be arranged in a way that permits comfortable
work posture. To ensure this
• Height of the chair should be such that top of the work table is about 50 mm below the
elbow level of the operator.
• Height of the table should be such that worker can work in both standing and sitting
positions.
• Flat foot rests should be provided for sitting workers.
• Figure 1.12 shows the situation with respect to bench heights and seat heights.
• The height and back of the chair should be adjustable.
• Display panel should be at right angles to the line or sight of the operator.
(f) An instrument with a pointer should be employed for check readings where as for
quantitative readings, digital type of instrument should be preferred.
(g) Hand tools should be possible to be picked up with least disturbance or rhythm and symmetry
of movements.

49.
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Process Planning and Cost Estimation
(h) Foot pedals should be used, wherever possible, for clamping declamping and for disposal
of finished work.
(i) Handles, levers and foot pedals should be possible to be operated without changing body
position.
(j) Work place must be properly illuminated and should be free from glare to avoid eye strain.
(k) Work place should be free from the presence of disagreeable elements like heat, smoke,
dust, noise, excess humidity, vibrations etc.
150 to 200 mm
Line of sight
90º
Display
95
105º to
º
Beach top
712 to
762 mm
0º to 5º
406 to
508 mm
Floor
Fig. 1.12: Bench and seat heights
Suggested work place layout
Figure 1.13 shows a work place layout with different areas and typical dimensions. It shows the
left hand covering the maximum working area and the right hand covering the normal working
area.
Normal working area
It is within the easy reach of the operator.
225
3
2
2
225
Work
Table
200
Fig. 1.13: Work place layout showing different areas and typical dimensions (mm)

50.
Work Study
33
Maximum working area
It is accessible with full arm stretch.
Figure 1.14 shows work place layout for assembling small component parts. A-1 is the actual
working area and the place of assembly (POA) where four component parts
P-1, P-2, P-3, and P-4 are assembled together. Bins containing P-1, P-2, P-3, and P-4 and commonly
employed tools (CET) (like screw driver, plier, etc.) lie in the normal working area A-2.
A-3
CET
-2
-2
A-3
A
A
ORT
PDA
A-1
PDA
Work
Table
Fig. 1.14: Work place layout for an assembly job
Occasionally required Tools (ORT) (hammers etc.) lie in the maximum working area A-3. After
the assembly has been made at POA, it is dropped into the cut portion in the work table – PDA
(Place for dropping assemblies) from where the assembly is delivered at its destination with the
help of a conveyer. This work place arrangement satisfies most of the principles of motion economy.
3. Other areas
Other areas include studies related to fatigue, losses caused due to fatigue, rest pauses, amount of
energy consumed, shift work and age considerations.
REVIEW QUESTIONS
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Define work study.
Explain the importance of working condition.
What do you mean by Ergonomics?
Define method study. What are the objectives of method study?
Explain the basic procedure for method study.
What are the types of charts used in method study?
Draw the symbols used in process chart.
Explain the operation process chart with an example.
What are types of flow process chart?
Explain main type flow process chart with an example.
Explain two-handed process chart with an example.
Explain man-machine chart.

51.
34
Process Planning and Cost Estimation
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
Explain flow diagram and string diagram.
What is work measurement?
What are the techniques used for work measurement?
Describe the procedure for conducting stop watch time study.
Define rating factor.
Compare flyhack and continuous method of stop watch measurement.
Define basic time. How will you calculate the basic time?
What is allowance? What are the various types of allowances.
What is standard time? How will you calculate it?
What is production study? State its uses.
What is ratio delay study and explain the procedure of ratio delay study?
Explain the procedure involved in synthesising from standard data.
Explain analytical estimating. State its advantages.
Define predetermined motion time study.
Define Ergonomics.
State the objectives of ergonomics.
Explain the application of ergonomics with an example.

52.
Unit–2
PROCESS PLANNING
2.0 INTRODUCTION
A process is defined as any group of actions instrumental to the achievement of the output of an
operation’s system in accordance with a specified measure of effectiveness.
When the product of the enterprise is designed, certain specifications are established; physical
dimensions, tolerances, standards, and quality are set forth. Then it becomes a matter of deciding
the specific details of how to achieve the desired output. This decision is the essence of process
planning.
2.1 PROCESS PLANNING—DEFINITION
Process planning has been defined as the sub-system responsible for the conversion of design data
to work instruction.
Process planning can also be defined as the systematic determination of the methods by which
a product is to be manufactured economically and competitively. It consists of devising, selecting
and specifying processes, machine tools and other equipment to convert raw material into finished
and assembled products.
2.1.1 Purpose of Process Planning
The purpose of process planning is to determine and describe the best process for each job so that,
1. Specific requirements are established for which machines, tools and others equipment
can be designed or selected.
2. The efforts of all engaged in manufacturing the product are coordinated.
3. A guide is furnished to show the best way to use the existing or the providing facilities.
Process planning is an intermediate stage between designing the product and manufacturing it
(figure 2.1).
Where the product design ends, the process planning begins. However, the basic process
planning must begin during the product design stages where the selection of materials and initial
forms, such as casting, forging and die casting take place. The accepted end point for production
design is manifested by the drawing release, which summarizes the exact specifications of what is

53.
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Process Planning and Cost Estimation
2.1.2 Concept of Process Planning
Design specification and requirements
Sales forecasts:
How many to make
Product
Planning
Production design, basic decisions
setting minimum possible costs
Design
Process
Functional design
Drawings and specifications
of what to make
Product analysis - assembly
charts and flow charts
Buy
Make - buy decisions
Make
Process decisions - selection from
alternative processes
Route sheet and operation
sheets; specification
of how to manufacture
Work place
and too design
Modifications of process plans
due to layout, quality preference
and machine availability
Manufacturing
Fig. 2.1: Overall development of processing plans

54.
Process Planning
37
to be made. Process planning takes over from this point and develops the broad plan of manufacture
for the part of product.
Process planning takes as its inputs the drawings or other specifications which indicate what is
to be made and how many are to be made.
The drawings are then analysed to determine the overall scope of the project. If it is a complex
assembled product, considerable effort may go into exploding the product into its components and
subassemblies.
Preliminary decisions about subassembly groupings to determine which parts to make and which
to buy, as well as to determine the general level of tooling expenditure, may be made at this point.
Then, for each part, a detailed routing is developed. Here technical knowledge of processes,
machines, and their capabilities is required, but of almost equal importance is a knowledge of
production economics.
In brief, the engineering drawing of the component is interpreted in terms of the manufacturing
process to be used. This step is referred to as process planning and it is concerned with the
preparation of a route sheet.
The route sheet is a listing of the sequence of operations which must be performed on the
component. It is called a route sheet because it also lists the machines through which the part
must be routed in order to accomplish the sequence of operations.
2.2 OBJECTIVES OF PROCESS PLANNING
The systematic determination of the engineering processes and systems to manufacture a product
competitively and economically is called operations planning. It is the stage between design and
production. The plan of manufacture considers functional requirements of the product, quantity,
tools and equipment, and eventually the costs for manufacture.
2.3 SCOPE OF PROCESS PLANNING
A process is defined as any group of actions instrumental to the achievement of the output of an
operations system in accordance with specified measure of effectiveness. When the product
designed, certain specifications are established; physical dimensions, tolerance, standards and quality
are set forth. Then it becomes a matter of deciding over the specific details of how to achieve the
desired output. This decision is the essence of process planning. The production function essentially
is a transformation process that accepts the inputs and gives the outputs after adding value to the
inputs. Process selection is a major strategic decision as it involves allocation of men and material
resources as well as financial commitments for a long period.
Operation planning is a responsibility of the manufacturing organization. A number of functional
staff arrangements are possible. This process leads to the same output despite organizational
differences. The following are business objectives for operations planning:
1. New product manufacture
A new design may have not been produced before or, alternatively, new manufacturing operations
may be introduced for the product. Unless there is planning, the product introduction will be
helter-skelter.
2. Sales
Opportunity for greater saleability of an existing or new product can develop from different

55.
38
Process Planning and Cost Estimation
colours, materials, finish, or functional and non-functional features. Sales and marketing departments
provide advice to help manufacturing planning.
3. Quantity
Changes in quantity require different sequences, tools, and equipment. The OP planner differentiates
for these fluctuations. If volume increases, the chance is for lower cost. In contrast, if volume
decreases, the cost should not increase out of reason. There may be a fortuitous opportunity for
reduced cost, if economics and technology will allow substitution of new process, training, and
resources even if quantities are reduced. If quantity reduces too much, however, it is appropriate
for the OP planner to recommend that production may no longer be economical, perhaps, a supplier
may be the appropriate lower cost alternative.
4. Effective use of facilities
Operation planning often can find alternate opportunities for the plant’s production facilities to take
up any slack that may develop. Seasonal products, which might be popular in the summer, need an
alternative product for the winter season. For example, companies that produce sporting equipment
may use the same facilities to produce tennis rackets and skis.
5. Cost reduction
Various opportunities become available if the company has an ongoing cost reduction effort.
Suggestion plans, value analysis, design for manufacturing (DFM), and directed and systematic
effort involve operations planning.
2.4 INFORMATIONS REQUIRED TO DO PROCESS PLANNING
1.
2.
3.
4.
5.
6.
7.
Quantity of work to be done along with product specifications.
Quality of work to be completed.
Availability of equipments, tools and personnels.
Sequence in which operations will be performed on the raw material.
Names of equipment on which the operations will be performed.
Standard time for each operation.
When the operations will be performed?
2.5 PROCESS PLANNING ACTIVITIES
2.5.1 Concept of Process Planning
The concept of process planning is to determine
1. The operations involved in the manufacture of each product.
2. The machines on which operations are to be done.
3. The tools, jigs and fixtures required.
4. The material requirements including scrap.
5. The speeds and feeds that are to be used.
6. The type of labour required.
7. The time required for each operation.
The above informations are made available on process sheet. The main objective of process
planning is to find the most economic method of performing an activity.

56.
Process Planning
39
The following informations are necessary to carry out this function effectively:
1. Product data.
2. Volume of production.
3. Quality requirements.
4. Equipments and personnel available.
5. Time available to perform the work or delivery date.
2.5.2
Preparing Operation Planning Sheet
The following informations are required to do the process planning effectively:
1. Quantity of work to be done along with product specifications.
2. Quality of work to be completed.
3. Availability of equipment, tools and personnel.
4. Sequence in which operations will be performed on the raw material.
5. Names of equipments on which the operations will be performed.
6. Standard time for each operation.
7. When the operations will be performed?
8. Cutting speed
9. Feed
10. Material specification.
11. Job rating of labours.
Operation planning sheet
Part Name:
Material Specification:
Operation
No.
…………
…………
Description
of Operation
Material: ………....
Machine
Tools
Part No.: ………...
Jigs
Gauges
2.5.3 Process Planning Procedure
1.
2.
3.
4.
5.
6.
7.
8.
Preparation of working drawings.
Deciding to make or buy.
Selecting manufacturing process.
Machine capacity and machine selection.
Selection of material and bill of materials.
Selection of jigs, fixtures and other attachments.
Operation planning and tooling requirement.
Preparation of documents such as operation sheet and route sheet etc.
Time
Analysis

57.
40
Process Planning and Cost Estimation
(a) Make or buy decision
Recommendations should be made whether to make or buy the material, part or assembly
informations should be sufficiently detailed to take intelligent decisions. Cost and availability of the
production capacity are the two important factors in arriving to make or buy decision.
Make
It requires appropriate production equipment, suitable personnel, material, adequate space,
supervisions, design standards and overheads maintenance, taxes, insurances, management attention
and other indirect and hidden costs.
Buy
It permits lower investments, small labour force, less handling, lower plant cost for building and up
keep, less overhead or taxes, insurance and supervision and less problems of man-management
relations.
A company has a choice of three alternatives before starting for a new product.
1. Purchase the product from a contracted manufacturer.
2. Purchase some components and materials and manufacture and assemble the balance in
its own plant.
3. Manufacture the product completely, starting with the extraction of basic raw materials.
(b) Determination of material requirements
The materials required are worked out and arrangements to procure them are made. The procedure
for examining the material requirements are given below.
1. Existing requirements for works on hand.
2. The new or extra material required. It is to be calculated from bill of materials.
3. Total material required.
4. Existing stock of materials.
5. Additional materials to be produced.
(c) Selection of material, jigs, fixtures etc.
The selection of material has become complicated by the great increase not only in the kinds of
materials but also in the various forms. The material should be of right quality and chemical
composition as per the product specifications. The shape and size of material should restrict the
scrap.
(i) Bill of material
The most common method of analyzing a product into component parts is through the use of bills
of material or specification sheets. Bill of material is a means of determining, purchasing and
production order requirements. It should indicate if the part is to be manufactured or purchased.
The production control department uses the bill of material to determine manufacturing and
scheduling dates.
Process engineering uses it as a check list to complete their work. Methods engineering uses
it in the preparation of time allowances for assembling operations. Accumulations are made by the
stores department according to the bills of materials. The releases by assembly units are made by
the finished stores department in accordance with the bills of material.
The design of the bill of material varies slightly in minor details. It depends upon the various
uses made of it by individual companies. The information usually required on the bill of material
form includes:

58.
Process Planning
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
41
The product name.
Product code identification
Sheet number.
Use.
Date of preparation.
Name of preparer.
Name of checker.
Item numbers.
Make/purchase designations.
Sub assembly part numbers and names.
Quantity requirements and,
Material used in each part.
Note: Bill of materials is also known as parts list.
Table 2.1: Bill of materials
Item Switch: S25
Drawing:
Sheet No: 2 of 5
A8
Assembly: 3 kW motor
Date:
Part
No.
Part
Name
No.
Item
Material
SJ-64
Drive
Spring
3
Spring steel
Quantity
per item
Cost per
item
Remarks
-
Rs.100/-
Purchase
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Prepared by…………………
Checked by ……………...
(ii) Selection of jigs, fixture and other special attachments
These supporting devices are necessary
1. To give higher production rate, and
2. To reduce the cost of production per piece.
(d) Selection of machinery
The selection of the correct machinery is closely related to the selected process of manufacturing.
But it is difficult to separate one from the other. However, there is a major difference between the
selection of a process and the selection of a machine.
Machines generally, represent long terms capital commitments. But process may be designed
for relatively short duration. The following factors must be taken into account while selecting a
correct equipment:
• The size and shape of the workpiece.
• The work material.

59.
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Process Planning and Cost Estimation
• The accuracy and surface quality required.
• The quantity of parts.
• The sizes of lots required and,
• Personal preferences.
1. If a number of surfaces are to be machines on a part, the choice is offered of machining
them separately, all together or in various combinations. If surfaces on a part are similar in
shape and size, they are better suited to being treated in one operation than if they are
different from one another.
2. More powerful machines may be needed to work hard material than soft material.
3. Work piece size and dimensions may dictate particular features that a machine tool must
have.
4. Small work pieces are handled on equipment different from that used for large parts. As
an example, small and medium size parts are turned on horizontal lathes, but short pieces
of large diameters are commonly machines on vertical lathes.
5. Small tolerance call for certain types of machine, whereas large tolerance does not call
for specific machine.
In general, very large parts must be produced by slower methods. As a result, they must be
produced on the larger and slower machines, mainly on a tool room basis. Smaller parts whose
shape is contributing to ease of handling can be produced on faster machines. They are more readily
adapted to mass production. They are exceptions in the pressed metal industry.
The size and shape of the workpiece associates itself closely with the size and type of machine
required to produce it. Choice may be made between general purpose machines (centre lathes,
planners, shapers, drill pressers etc.) and special purpose machines.
The general purpose machines have the following characteristics:
1. Usually less initial investment in machines.
2. Greater machine flexibility.
3. Fewer machines may be required.
4. Less maintenance cost.
5. Less set up and debugging time.
6. Less danger of obsolescence.
The special purpose machines have the following characteristics:
1. Uniform product flow.
2. Reduced in process inventory.
3. Reduced man power requirements.
4. Reduced factory floor space.
5. Higher output.
6. Higher product quality.
7. Reduced inspection cost.
8. Reduced operator skill requirements.
The machines and equipment that will do a job at the lowest total cost are the ones that should
be selected. Direct, overhead and fixed costs should be considered. Generally, more items put into
one operation. The lesser the handling time, the more the chance for simulation and the lower the

60.
Process Planning
43
direct costs. But the operation is likely to become more complex, calling for more expensive machine.
As a rule, a high rate of production justifies a largest investment in machine to reduce direct costs.
To select machine tools, an investigation must be made to ascertain the aptitude, range and
capacity required for the job. Each type of machine is best suited for certain kind of work. Lathes
for turning, drilling machines for holes. A machine must have adequate range and capacity for the
work it is to do.
The factors determining the range and capacity may be the size of the work piece, the working
area, length of stroke, speeds, feed, forces and power required.
Personal preference or specific conditions may influence the selection of a machine tool. A
particular type of make of machine may be favoured, because a person in the past found it
dependable, easy to operate, safe and accurate. Often a new machine is not purchased if one
almost as good is already in the plant and not fully loaded.
(e) Operation planning sheet
A process plan is a complete concept of a process. It is recorded and transmitted in a number of
ways to suit various conditions. In a small plant or where skilled workers may be relied upon to
perform without detailed instructions, process plans may be recorded quite incompletely. In a large
organization with a complex product and highly refined procedures, process plans may be recorded
in minute details.
Process sheet and its necessity
Table 2.2: Process sheet
Part description .........
Drawing number .........
Material specification .........
Quantity required per unit .........
(Inclusive of scrap)
Sl.
No.
Dept.
Operation
Part No.
Assembly No.
Lot size
Issued by
Material size .........
Machine
Code
Tools
Labour
Code
Speed
Feed
Set-up
Time
.........
.........
.........
.........
Standard
Time
A process planning medium almost universally used is the routing also known as route sheet,
process sheet and operation planning sheet. It lists and describes the operations of a process.
Routings are written as briefly as possible to save time. They completely designate departments,
machines, tools, etc. The operation sheet form will vary for different companies. However, the
description of the operation special instructions is usually similar.
A process sheet is a manufacturing engineering document. It should be sufficiently explicit so
that operational personnel (example: workers) can perform every operation/function necessary to
produce the finished component and that operations can establish staffing and piece cost from which
to judge operation efficiency during and after physically launching the operation.
The process sheet contains columns for recording operations, tools, types of machine used,
speed, feed, times etc.